[ JPA ] 9. 임베디드 타입 활용

Reference. 한 번에 끝내는 Java/Spring 웹 개발 마스터 초격차 패키지 Online

이전 글

1. Repository interface 메서드 - 1

2. Query Method 정의 및 실습 - 2

3. Entity 기본 속성 - 3

4. Entity Listener - 4

5-1. Entity Relations - 5 (ERD, 데이터베이스 기준 연관 관계)

5-2. Entity Relations - 5 ( 1:1 @OneToOne )

5-3. Entity Relations - 5 ( 1:N @OneToMany )

5-4. Entity Relations - 5 ( N:1 @ManyToOne )

5-5. Entity Relations ( N:N @ManyToMany )

6-1. 영속성 컨텍스트(Persistence Context)

6-2. Entity 캐시

6-3. Entity 생명주기

6-3. Entity 생명주기

7. 영속성 전이 (Cascade)

8. 커스텀 쿼리 사용

9. 임베디드 타입 활용

• 현업에서 많이 사용하는 임베디드 타입
  • 주문시의 가격 필드
  • 주소 정보 (도, 시 군, 구, 상세주소)

• @Embeddable, @Embedded 어노테이션을 이용해 임베디드할 객체와 Entity 속성을 설정

@Embeddable, @Embedded 사용 예시

User.java

public class User extends BaseEntity{
		...
		@Embedded
		private Address address;
}

Address.java 생성

@Embeddable
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Address {
    private String city; //시
    private String district; //구

    @Column(name = "address_detail")
    private String detail; //상세주소

    private String zipCode; //우편번호
}

UserEntityListener.java 수정(User컬럼이 수정되면 수정 필요)

public class UserEntityListener {
    @PostPersist
    @PostUpdate
    public void postPersistAndPostUpdate(Object o){
        UserHistoryRepository userHistoryRepository = BeanUtils.getBean(UserHistoryRepository.class);

        User user = (User) o;
        UserHistory userHistory = new UserHistory();
        userHistory.setName(user.getName());
        userHistory.setEmail(user.getEmail());
        userHistory.setUser(user);
        userHistory.setAddress(user.getAddress());

        userHistoryRepository.save(userHistory);
    }
}

테스트 코드 및 결과

//UserRepositoryTest.java
@Test
void embedTest(){		
		User user = new User();
    user.setName("steve");
    user.setAddress(new Address("서울시", "강남구", "강남대로 364 미왕빌딩", "06242"));

    userRepository.save(user);

		userRepository.findAll().forEach(System.out::println);
}

//결과
Hibernate: 
    
    create table user (
       id bigint not null auto_increment,
        created_at datetime(6) default now(6) comment '생성시간' not null,
        updated_at datetime(6) default now(6) comment '수정시간' not null,
        city varchar(255),
        address_detail varchar(255),
        district varchar(255),
        zip_code varchar(255),
        email varchar(255),
        gender integer,
        name varchar(255),
        primary key (id)
    ) engine=InnoDB

Hibernate: 
    insert 
    into
        user
        (created_at, updated_at, city, address_detail, district, zip_code, email, gender, name) 
    values
        (?, ?, ?, ?, ?, ?, ?, ?, ?)

User(super=BaseEntity(createdAt=2021-08-14T23:08:27, updatedAt=2021-08-14T23:08:27), id=1, name=martin, email=martin@fastcampus.com, gender=null, address=null)
User(super=BaseEntity(createdAt=2021-08-14T23:08:27, updatedAt=2021-08-14T23:08:27), id=2, name=dennis, email=dennis@fastcampus.com, gender=null, address=null)
User(super=BaseEntity(createdAt=2021-08-14T23:08:27, updatedAt=2021-08-14T23:08:27), id=3, name=sophia, email=sophia@slowcampus.com, gender=null, address=null)
User(super=BaseEntity(createdAt=2021-08-14T23:08:27, updatedAt=2021-08-14T23:08:27), id=4, name=james, email=james@slowcampus.com, gender=null, address=null)
User(super=BaseEntity(createdAt=2021-08-14T23:08:27, updatedAt=2021-08-14T23:08:27), id=5, name=martin, email=martin@another.com, gender=null, address=null)
User(super=BaseEntity(createdAt=2021-08-14T23:08:28.430528300, updatedAt=2021-08-14T23:08:28.430528300), id=6, name=steve, email=null, gender=null, address=Address(city=서울시, district=강남구, detail=강남대로 364 미왕빌딩, zipCode=06242))

임베디드 타입의 다른 예시 (재활용)

User.java

• @AttributeOverrides, @AttributeOverride를 통해 Address.java객체의 컬럼 재정의
  • 재정의 하지 않으면 User테이블에 같은 컬럼이 중복되어 오류 발생

@Embedded
@AttributeOverrides({
    @AttributeOverride(name = "city", column = @Column(name = "home_city")),
    @AttributeOverride(name = "district", column = @Column(name = "home_district")),
    @AttributeOverride(name = "detail", column = @Column(name = "home_detail")),
    @AttributeOverride(name = "zipCode", column = @Column(name = "home_zipCode"))
})
private Address homeAddress;

@Embedded
@AttributeOverrides({
    @AttributeOverride(name = "city", column = @Column(name = "company_city")),
    @AttributeOverride(name = "district", column = @Column(name = "company_district")),
    @AttributeOverride(name = "detail", column = @Column(name = "company_detail")),
    @AttributeOverride(name = "zipCode", column = @Column(name = "company_zipCode"))
})
private Address companyAddress;

UserEntityListener.java

public class UserEntityListener {
		...
		public void postPersistAndPostUpdate(Object o){
				...
				userHistory.setUser(user);
				userHistory.setHomeAddress(user.getHomeAddress());
		    userHistory.setCompanyAddress(user.getCompanyAddress());
		
				userHistoryRepository.save(userHistory);
		}
}

테스트 코드 및 결과

//UserRepositoryTest.java
@Test
void embedTest(){		
		User user = new User();
    user.setName("steve");
    user.setHomeAddress(new Address("서울시", "강남구", "강남대로 364 미왕빌딩", "06242"));
    user.setCompanyAddress(new Address("서울시", "성동구", "성수이로 113 제강빌딩", "04794"));

    userRepository.save(user);

		userRepository.findAll().forEach(System.out::println);
}

//실행결과
Hibernate: 
    
    create table user (
       id bigint not null auto_increment,
        created_at datetime(6) default now(6) comment '생성시간' not null,
        updated_at datetime(6) default now(6) comment '수정시간' not null,
        company_city varchar(255),
        company_detail varchar(255),
        company_district varchar(255),
        company_zip_code varchar(255),
        email varchar(255),
        gender integer,
        home_city varchar(255),
        home_detail varchar(255),
        home_district varchar(255),
        home_zip_code varchar(255),
        name varchar(255),
        primary key (id)
    ) engine=InnoDB

Hibernate: 
    insert 
    into
        user
        (created_at, updated_at, company_city, company_detail, company_district, company_zip_code, email, gender, home_city, home_detail, home_district, home_zip_code, name) 
    values
        (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate: 
    insert 
    into
        user_history
        (created_at, updated_at, company_city, company_detail, company_district, company_zip_code, email, gender, home_city, home_detail, home_district, home_zip_code, name, user_id) 
    values
        (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)

User(super=BaseEntity(createdAt=2021-08-14T23:34:19, updatedAt=2021-08-14T23:34:19), id=1, name=martin, email=martin@fastcampus.com, gender=null, homeAddress=null, companyAddress=null)
User(super=BaseEntity(createdAt=2021-08-14T23:34:19, updatedAt=2021-08-14T23:34:19), id=2, name=dennis, email=dennis@fastcampus.com, gender=null, homeAddress=null, companyAddress=null)
User(super=BaseEntity(createdAt=2021-08-14T23:34:19, updatedAt=2021-08-14T23:34:19), id=3, name=sophia, email=sophia@slowcampus.com, gender=null, homeAddress=null, companyAddress=null)
User(super=BaseEntity(createdAt=2021-08-14T23:34:19, updatedAt=2021-08-14T23:34:19), id=4, name=james, email=james@slowcampus.com, gender=null, homeAddress=null, companyAddress=null)
User(super=BaseEntity(createdAt=2021-08-14T23:34:19, updatedAt=2021-08-14T23:34:19), id=5, name=martin, email=martin@another.com, gender=null, homeAddress=null, companyAddress=null)
User(super=BaseEntity(createdAt=2021-08-14T23:34:20.112342100, updatedAt=2021-08-14T23:34:20.112342100), id=6, name=steve, email=null, gender=null, homeAddress=Address(city=서울시, district=강남구, detail=강남대로 364 미왕빌딩, zipCode=06242), companyAddress=Address(city=서울시, district=성동구, detail=성수이로 113 제강빌딩, zipCode=04794))

임베디드 타입의 null을 넣을 경우

• null, 빈객체로 넣는 경우 임베디드 된 모든 컬럼의 값은 null로 저장

UserRepository.java

• 실제 데이터베이스의 결과 확인을 위해 findAllRowRecords 생성

@Query(value = "select * from user", nativeQuery = true)
List<Map<String, Object>> findAllRowRecords();

UserRepositoryTest.java

@Test
void embedTest(){
		User user = new User();
    user.setName("steve");
    user.setHomeAddress(new Address("서울시", "강남구", "강남대로 364 미왕빌딩", "06242"));
    user.setCompanyAddress(new Address("서울시", "성동구", "성수이로 113 제강빌딩", "04794"));

    userRepository.save(user);

    User user1 = new User();
    user1.setName("joshua");
    user1.setHomeAddress(null);
    user1.setCompanyAddress(null);

    userRepository.save(user1);

    User user2 = new User();
    user2.setName("jordan");
    user2.setHomeAddress(new Address());
    user2.setCompanyAddress(new Address());

    userRepository.save(user2);

    userRepository.findAll().forEach(System.out::println);
    userRepository.findAllRowRecords().forEach(a -> System.out.println(a.values()));
}

실행결과

• JPA에서 객체와 null로 넣을때 결과 차이가 발생하는 이유는 영속성 컨텍스트 캐쉬 때문
  • EntityManager clear()를 실행하면 DB에서 조회하기 때문에 둘 다 null로 표시

//JPA를 이용한 조회 (userRepository.findAll()
User(super=BaseEntity(createdAt=2021-08-14T23:40:54.880805400, updatedAt=2021-08-14T23:40:54.880805400), id=6, name=steve, email=null, gender=null, homeAddress=Address(city=서울시, district=강남구, detail=강남대로 364 미왕빌딩, zipCode=06242), companyAddress=Address(city=서울시, district=성동구, detail=성수이로 113 제강빌딩, zipCode=04794))
User(super=BaseEntity(createdAt=2021-08-14T23:40:55.034806400, updatedAt=2021-08-14T23:40:55.034806400), id=7, name=joshua, email=null, gender=null, homeAddress=null, companyAddress=null)
User(super=BaseEntity(createdAt=2021-08-14T23:40:55.041805400, updatedAt=2021-08-14T23:40:55.041805400), id=8, name=jordan, email=null, gender=null, homeAddress=Address(city=null, district=null, detail=null, zipCode=null), companyAddress=Address(city=null, district=null, detail=null, zipCode=null))

//데이터베이스 조회 (userRepository.findAllRowRecords())
[6, 2021-08-14 23:37:26.221536, 2021-08-14 23:37:26.221536, 서울시, 성수이로 113 제강빌딩, 성동구, 04794, null, null, 서울시, 강남대로 364 미왕빌딩, 강남구, 06242, steve]
[7, 2021-08-14 23:37:26.406535, 2021-08-14 23:37:26.406535, null, null, null, null, null, null, null, null, null, null, joshua]
[8, 2021-08-14 23:37:26.416538, 2021-08-14 23:37:26.416538, null, null, null, null, null, null, null, null, null, null, jordan]